Handheld belt sander

ABSTRACT

A handheld belt sander includes a main body having a motor connected with a rotating wheel and a base extending along a first straight direction. A mount is fixed to the base. A straight rod extending along a second straight direction with no bend is disposed on the mount. The second straight direction is upward from the first straight direction at a raise angle. A roller is disposed on the straight rod. A flat plate extending under the straight rod is disposed on the mount. A grinding belt encircles the rotating wheel, the roller and the flat plate and is tightened by the straight rod. A lower part of the grinding belt under the straight rod abutted against the flat plate. A space to be entered for the grinding belt formed between the straight rod and an upper part of the grinding belt above the straight rod.

FIELD OF THE INVENTION

The present invention relates to a hand tool for grinding, and more particularly to a handheld belt sander.

BACKGROUND OF THE INVENTION

A conventional belt sander as shown in FIG. 7 has a main body 7 with a rotating wheel 71 driven by a motor. A handle 72 is formed at a rear end of the main body 7. A rod 73 extends from a fore end of the main body 7. A grinding belt 8 encircles the rod 73 and the rotating wheel 71 and is driven by the rotating wheel 71 functioned by the motor to grind a surface on an item.

However, the rod 73 extends forwardly from the main body 7 in a straight direction, tightening the grinding belt 8 to be very close to the rod 73. Being stopped by the rod 73, the grinding belt 8 is not able to move to an appropriate position to fit an arc surface for grinding. Then the arc shape of the ground surface may be damaged.

Besides, when using the conventional belt sander to grind on a flat surface of an item, user must twist his wrist to make the grinding belt 8 parallel to the flat surface to engage with the ground surface completely due to the same straight extension direction of the handle 72 and the rod 73. User's wrist may feel unwell after a long time use.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a handheld belt sander having a straight rod extending upward from the body of the belt sander at an angle for tightening a grinding belt, forming a space between the straight rod and the grinding belt for being entered by the grinding belt when pressed. It is suitable to grind arc surfaces of items and keeps a good hand posture to avoid damages when grinding on flat surfaces.

In order to achieve the above object, a handheld belt sander is provided. The handheld belt sander comprises a main body, a base, a mount, a straight rod and a grinding belt. The main body has a motor connected with a rotating wheel. The base is formed at a fore end of the main body and extends along a first straight direction. The mount is fixed to the base through a first positioning portion of the base and a second positioning portion of the mount to prevent the mount from rotating relative to the base. The straight rod extending along a second straight direction with no bend is disposed on the mount, wherein the second straight direction is upward from the first straight direction at a raise angle. A roller is disposed at an end of the straight rod. A flat plate extending under the straight rod is disposed on the mount. The grinding belt encircles the rotating wheel, the roller and the flat plate and is tightened by the straight rod. A lower part of the grinding belt under the straight rod abuts against the flat plate. A space to be entered for the grinding belt is formed between the straight rod and an upper part of the grinding belt above the straight rod, so that the grinding belt moves into the space after being pressed.

In an embodiment, the mount extends along the second straight direction and has a hole extending along the second straight direction for coupling with the straight rod.

In another embodiment, the mount extends along the first straight direction and has a hole extending along the second straight direction for coupling with the straight rod.

Preferably, the raise angle is 15 degrees.

Preferably, the first positioning portion is one of a concave and a convex in a shape of noncircle while the second positioning portion is the other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view in accordance with a first embodiment of the present invention;

FIG. 2 is an exploded view in accordance with the first embodiment of the present invention;

FIG. 3 is a schematic view in accordance with the first embodiment of the present invention;

FIG. 4 and FIG. 5 are schematic view in accordance with the first embodiment of the present invention when in use;

FIG. 6 is a schematic view in accordance with a second embodiment of the present invention;

FIG. 7 is a perspective view of conventional handheld belt sander.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

Referring to FIG. 1, FIG. 2 and FIG. 3, a handheld belt sander in accordance with a first embodiment of the present invention comprises a main body 1 having a fore end and a rear end. A motor 11 is disposed on the main body 1 and connects with a rotating wheel 12 driven by the motor 11. The fore end of the main body 1 is provided with a base 14 extending forward from the main body 1 along a first straight direction D1. The rear end of the main body 1 is provided with a handle 13 extending backward from the main body 1 along a direction reverse to the first positioning portion D1.

A mount 2 is fixed to the base 14. In detail, a first positioning portion is provided on the base 14 while a second positioning portion is provided on the mount 2. In this embodiment, the first positioning portion is a rectangular concave 141, and the second positioning portion is a rectangular convex 21. By inserting the rectangular convex 21 into the rectangular concave 141, the mount 2 is not able to rotate relative to the base 14. However, not limited to rectangle, as long as shapes of the first positioning portion and the second positioning portion are noncircular, the mount 2 is not able to rotate relative to the base 14.

As shown in FIG. 3, the mount 2 extends along a second straight direction D2 which is upward from the first straight direction D1 at a raise angle a The mount 2 is provided with a hole 22 extending along the second straight direction D2 for inserting a straight rod 3 with no bend. Depending on the extension of the hole 22, the straight rod 3 extends outward of the hole 22 along the second straight direction D2. Therefore, the straight rod 3 is upward from the base 14, the main body 1 and the handle 13 at the raise angle a In this embodiment, the raise angle A is 15 degrees. Moreover, a roller 31 is assembled at an end of the straight rod 3.

A bottom of the mount 2 is provided with a long flat plate 4, which is under the straight rod 3. A grinding belt 5 encircles the rotating wheel 12, the roller 31 and the flat plate 4 and is tightened by the straight rod 3. The grinding belt 5 can be divided into a lower part and an upper part according to the location of the straight rod 3. The lower part of the grinding belt 5 is under the straight rod 3 and abuts against the flat plate 4 to be defined as a flat straight section 51 as a result of the grinding belt 5 being tightened. On the other hand, the upper part of the grinding belt 5 is above the straight rod 3, and a space 52 is formed between the straight rod 3 and the upper part of the grinding belt 5 due to the raise angle a When the upper part of the grinding belt 5 is pressed, it changes to curve and move into the space 52.

Referring to FIG. 4, when using the belt sander to grind on a flat surface 61 of an item, the flat straight section 51 of the grinding belt 5 can be engaged with the surface 61 completely. At this time, user can hold the handle 13 in a natural wrist posture because of the tilted straight rod 3 at the raise angle 8, so that user's wrist is not twisted to get hurt.

Moreover, referring to FIG. 5, when using the belt sander to grind on an arc surface 62 of an item, the upper part of the grinding belt 5 is pressed by the item to curve. At this time, the space 52 is provided for the grinding belt 5 being curved by the operating force from user. Thus, the grinding belt 5 can be curved in an appropriate way so as to ensure the arc surface 62 from grinding over.

A second embodiment of the present invention is shown in FIG. 6. The structure of this embodiment is based on the structure of the previous embodiment. However, orientations of the mount 2 and the hole 22 are changed but it still achieves the goal that the straight rod 3 tilts from the main body 1 and the handle 13 at the raise angle a In this embodiment, like the base 14, the mount 2 extends along the first straight direction Dl. The hole 22 extends along the second straight direction D2. Consequently, the straight rod 3 inserted in the hole 22 extends along the second straight direction D2 to be upward from the main body 1 and the handle 13 at the raise angle a

Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims. 

What is claimed is:
 1. A handheld belt sander, comprising: a main body having a motor connected with a rotating wheel; a handle formed at a rear end of the main body; a base formed at a fore end of the main body and extending along a first straight direction, the base having a first positioning portion; a mount disposed on the base, the mount having a second positioning portion to be fixed to the first positioning portion to prevent the mount from rotating relative to the base; a straight rod extending along a second straight direction with no bend disposed on the mount, wherein the second straight direction is upward from the first straight direction at a raise angle; a roller disposed at an end of the straight rod; a flat plate disposed on the mount, the flat plate extending under the straight rod; a grinding belt encircling the rotating wheel, the roller and the flat plate and tightened by the straight rod, a lower part of the grinding belt under the straight rod abutted against the flat plate to be defined as a flat straight section, a space to be entered for the grinding belt formed between the straight rod and an upper part of the grinding belt above the straight rod, so that the grinding belt moves into the space after being pressed.
 2. The handheld belt sander as claimed in claim 1, wherein the mount extends along the second straight direction and has a hole extending along the second straight direction for coupling with the straight rod.
 3. The handheld belt sander as claimed in claim 1, wherein the mount extends along the first straight direction and has a hole extending along the second straight direction for coupling with the straight rod.
 4. The handheld belt sander as claimed in claim 1, wherein the raise angle is 15 degrees.
 5. The handheld belt sander as claimed in claim 1, wherein the first positioning portion is one of a concave and a convex in a shape of noncircle while the second positioning portion is the other. 